1. Nerlens Noel, Kentucky

Andy Lyons/Getty Images

Nerlens Noel offers the full defensive package as an elite NBA rim protector.

His physical measurements are excellent, standing 6'11'' with a 7'4'' wingspan and 9'1.5'' standing reach. From the waist down, he's explosive, showing the ability to get high above the rim and challenge everything around the cylinder. Above the waist, he's a physical specimen with a chiseled upper body and strong, cut arms that mimic a wall when raised straight up.

He's a two-way interior defender in that he's strong enough to defend the post as a back-to-the-basket deterrent and can block shots off the ball thanks to his length, explosiveness and athleticism.

Noel has top top-five upside because of his ability to alter an opponent's offensive game plan.

2. Alex Len, Maryland

Kevin C. Cox/Getty Images

Alex Len has quickly risen up draft boards because of his two-way potential, not just his offense.

Standing 7'1'' with a matching wingspan and explosive athleticism, Len is a natural rim protector regardless of IQ or instincts. His presence alone forces tough floaters and makes it difficult for bigs to get clean, open layups.

Len's shot-blocking rate was as high as anyone's in the country, swatting 2.1 shots a game in only 21 minutes of action. He's shown sound footwork and obvious mobility that essentially decreases the size of the goal he's protecting.

The tools are all there. He should be averaging 3.5 blocks per game in a more regular role as a sophomore.

3. Rudy Gobert, Chalet

The idea here is simple: The more space a player is capable of occupying, the less room for scorers to operate.

We're probably going to beat it over the head the whole year, but a 7'9'' wingspan is simply unprecedented. Arms that long belong on a mythical creature, not an athlete.

But when you combine this type of length with Gobert's motor and mobility, he becomes a ubiquitous presence from the high to low post. It will allow him to block shots on the weak-side while defending the strong one. If he's caught out of position, no fear. Some centers have recovery speed; Gobert has recovery length.

To put it in perspective, his arms cover four more inches of air than Anthony Davis'. I'm pretty sure I've seen him tie his shoe standing up.

4. Jeff Withey, Kansas

Richard Mackson-US PRESSWIRE

Jeff Withey's most appealing defensive attribute, other than having a head that sits seven feet from the floor, is his clean, effective footwork. He can guard both face-up and back-to-the-basket forwards and centers.

Withey isn't your typical rim protector, lacking the athleticism, strength and hops you see from guys like Dwight Howard and Serge Ibaka. But Withey's ability to glide from the high post to the low block while maintaining an effective defense angle makes it difficult for his man to get good looks inside.

His numbers last year were sick, for lack of a better word. He averaged 3.6 blocks a game in only 25 minutes of action.

Withey is regarded as a first-round prospect, and it's not because of his scoring prowess. Though more likely a long-term backup center rather than a 30-minute anchor, Withey projects as a reliable rim protector who gives a team's second unit some defensive stability down low.

5. Gorgui Dieng, Louisville

His body has continued to develop, and he now looks the part of a legitimate NBA center. One of the areas in which Dieng has improved is his coordination, a quality difficult to change. His timing and movement went from awkward to smooth, and it's shown both on the glass and as a shot-blocker.

More agile now than when he started, Dieng has become one of the premier defensive anchors in college basketball. If Louisville keeps winning, it will reflect nicely on his resume.

6. Michael Snaer, Florida State

He takes pride in locking down defenders, an attractive quality from someone who teams will be looking at to be a specialty ball-stopper. He's got that "Revis Island"-like confidence, with the goal of stranding the other team's best scorer.

Though perimeter defenders don't get the same love as rim protectors, Snaer makes opposing scorers work extra hard, which pays dividends at the end of games when fatigue becomes a factor. Making life hell for his assignment will be his primary job requirement if called upon in June.

7. Tony Mitchell, North Texas

Andrew Fielding-US PRESSWIRE

Labeled a combo-forward who should see time on the perimeter and interior, Tony Mitchell's defensive impact will be felt from arch to baseline.

Physically, he's strong, long and mobile, which leads to deflections and tips on passes and shots. Though slightly undersized for your natural power forward, Mitchell's leaping ability gives him room for error. Sometimes he mistimes his jump, yet can still alter the shot because of his hang-time and length. He also has a quick second jump, which negates the effectiveness of a good pump fake.

Though he offers versatile physical tools, his mindset is what makes him such a feared defense presence. Mitchell plays with a ferociousness to him, remaining ball-aggressive through entire defensive possessions.

Though Mitchell won't keep up his college shot-blocking rate in the pros (three blocks in 29 minutes), his court coverage and ability to change plays should make him a defensive asset at the next level.

8. James McAdoo, North Carolina

Bob Donnan-US PRESSWIRE

James McAdoo's physical tools are ideal for defending next level competition.

At 6'9'', McAdoo has the strength and upper body to defend most power forwards. Though it's more likely he'll defend hybrid 4s like Josh Smith, Thaddeus Young and Lamar Odom because of his agility, he wouldn't be a liability manning the post.

But his real appeal stems from his versatility and the defensive flexibility he can provide a rotation. McAdoo has small forward lockdown potential because of his foot speed, elite athleticism and dominant size. He's the type of guy coaches would want to stick on LeBron James or Kevin Durant because of his physical stature and relentless work ethic.

There's just so many things you can do with McAdoo defensively. He'll be a two-way athlete at the next level.

10. Victor Oladipo, Indiana

Steve Dykes-US PRESSWIRE

If Victor Oladipo hears his name called in June, it's because someone fell in love with his defensive potential.

Oladipo has all the physical tools required to lock down opposing scoring guards, including lateral quickness, strength and length. He gets low in his defensive stance, making it difficult for his man to get off too many purposeful dribbles.

Though not exactly the most dynamic offensive player, Oladipo has appeal as a offensive slasher and defensive perimeter asset. Those guys always find ways into rotations.

11. Mason Plumlee, Duke

Mark Dolejs-US PRESSWIRE

It's no secret that Plumlee's size, mobility and athleticism are the selling points here.

Defensively, Plumlee will act as an off-ball shot-blocker whose speed could allow him to be in two spots at once. He's got the potential to cover a ton of ground and aerial territory, with his quickness and leaping abilities acting as the drive force.

Above the rim is becoming an increasingly popular place to operate, and Plumlee happens to be familiar with that lifestyle. His coordination, running and jumping ability make him an excellent candidate to make defense plays off the ball.

13. CJ Aiken, Saint Joseph's

Howard Smith-US PRESSWIRE

There's plenty of long, athletic big men out there. But only few have the defensive instincts to become an elite shot-blocking presence.

Aiken's ability to anticipate, time and execute as an off-ball defensive rim protector gives the impression that he actually has three arms. He's averaged 3.5 blocks per game in back-to-back years, playing 27 minutes and 31 minutes, respectively. That's an incredible rate for a 6'9'' forward.

Physically, he's long, athletic and explosive, three qualities that translate to effective off-ball rim protection. He projects more as a weak-side shot-blocker, someone who can gamble a little bit, sneak away from his man and act as a roaming defensive presence because of his mobility and leaping abilities.

We've seen a ton of power forwards with similar physical strengths, but it's Aiken's defensive instincts that separate him from some of the other shot-blocking prospects.

14. Shabazz Napier, Connecticut

View Agency-US PRESSWIRE

Guards defended by Shabazz Napier have considered getting restraining orders.

He doesn't portray your typical ball-stopper, and a 6'1'', can essentially only guard opposing point guards. But I've seen Napier make some of them so distraught that they couldn't wait to give up the ball.

He needs to show up on a more consistent basis, but if a coach can get to him to keep his motor revved, Napier has the potential to unleash perimeter defensive mayhem.